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Phytohgia (Augnst2007) 89(2) 193 TWO NEW SPECIES 0¥AGERATINA (ASTERACEAE: EUPATORIEAE) FROM MEXICO B. L. Turner Plant Resources Center The University ofTexas at Austin Austin, Texas 78712 email [email protected] ABSTRACT Two new species ofAgeratina (subgenus Neogreenella) are described from Mexico: A. humochica B.L. Turner and/I. serboana B.L. Turner, both from the state ofOaxaca. Their relationships to previously described taxa are discussed and photographs oftheir holotypes are provided. KEY WORDS: Ageratina, Asteraceae, Mexico, Oaxaca Routine identification ofMexican Asteraceae has revealed the following novelties: AGERATINA HUMOCHICA B.L. Turner, sp. nov. Fig 1 Ageratina pendida Panero & Villasenor similis sed differt habitu robuste subfruticoso (vs herba perennis), foliis plerumque altemis (vs. oppositis), et capitulis multo majoribus. Robust herbs or subshrubs to 1 m (?) high. Stems densely glandular- pubescent. Leaves markedly alternate; petioles 1.5-2.5 cm long; blades cordate, nigose, glandular-pubescent above and below, their margins crenulate throughout. Capitulescence a terminal somewhat pendulous panicle 6-10 cm high and about as wide; ultimate peduncles 1-2 cm long. Heads 12-15 mm high; involucres composed of ca 30 linear- mm lanceolate, somewhat gradate, bracts 6-12 long. Receptacles mm plane, glabrous, 3-4 across. Florets numerous; corollas glabrous, mm mm mm ca. 8 long, the tubes 2-3 long. Achenes 3-4 long, sparsely pubescent with ascending short hairs; pappus ofca 30 readily mm deciduous tawny-white bristles ca 6 long. 194 Phytologia (August2007) 89(2) TYPE: MEXICO. OAXACA: Districto Ixtlan, 43 km N of Ixtlan de Juarez, "Steep slope along crest with Quercus andSymplociis northwest slope of Cerro Humo Chico" 2870 m, 6 Nov 1983, Breedlove & Almeda 600/7(holotype: TEX). In my treatment of Ageratina for the Comps of Mexico (Turner 1997)A. humochica, because ofits alternate upper stem leaves, will key to or near A. thyrsijlora, which it resembles not at all. It appears closest to the recently described A. pendula as noted in the above diagnosis, which is also an Oaxacan species (from Districto Juxtlahuaca). The latter taxon was not accounted for in my Mexican account. The novelty is named for Cerro Chico Humo, where first collected. AGERATINA SERBOANA B L Turner, sp. nov. Fig 2 Ageratinajosepaneroi B.L. Turner similis sed differt capitulescentiis omnino glandulosi-pubescentibus (vs. puberulis) et pedunculis ultimis 3-6 cm longis (vs 0.5-1.0 cm). Perennial herbs 60-70 cm high, the shoots presumably arising from slender ligneous rhizomes. Stems purplish, the lower portions with a mm vestiture ofcrinkly spreading hairs to 1 long, these underlain by a dense array of much shorter glandular hairs, the latter becoming the sole pubescence along the upper branches. Leaves opposite throughout, the intemodes mostly 5-10 cm long; petioles 2-3 cm long; blades deltoid to semicordate, marginally crenate, pubescent above and below, more so beneath, the lower surface moderately glandular- punctate. Captulescence a very loose terminal panicle ca 28 cm long, 12 cm across, the ultimate peduncles 3-6 cm long, densely glandular- mm pubescent. Involucre ofca 10 linear-lanceolate subequal bracts 6-8 mm long. Receptacle plane, ca 2 across, glabrous. Florets 25-30; mm mm mm corollas white, ca 6 long, the tube ca 2 long, the lobes ca 1 mm long. Achenes ca 5 long, pubescent with ascending short hairs; mm pappus of ca 30 slender bristles 5-6 long arranged in a single series. Phytohgia (Augiist 2007) 89(2) 195 TYPE: MEXICO. OAXACA: Mpio. Santago Textitlan, Cerro el Briche, pine oak forests, 1884 m, 21 Jul 2006, Rosario Tnijillo Vasquez 138 (holotype TEX). Ageratinaserboana belongs to the subgenus Neogreenella and will key to ornearA. cardiophylla in my treatment oiAgeratina forthe Comps of Mexico (Turner 1997). Unfortunately, A. josepaneroi, with which the present species is compared in the above diagnosis, was described (Turner 1996) aftermy Comp treatment went to press. The species name, "serboana," reflects the acronym of Sociedad para el Estudio de los Recursos Bioticos de Oaxaca, which funded collection ofthe type concerned. ACKNOWLEDGEMENTS I am grateful to my longtime colleague, Guy Nesom, for providing the Latin diagnoses and for his review of the manuscript. Emily Lott suggested the species name and also reviewed the paper. LITERATURE CITED Turner, B. L. 1996. Two remarkable novelties oiAgeratina (Asteraceae: Eupatorieae) Mexico. Phytologia 81: 343-347. Turner, B. L. 1997. Ageratina, in the Comps ofMexico, Eupatorieae. Phytologia Memoirs 11: 10-50. 196 Phytologia (August2007) 89(2) UhJVfHSlTVOf li^vncvUcuM Sliftp M pi. «lofi< sTCiX itilkriyersuA lllliiiiii Fig. 1.Ageratinahumochica (Holotype). Phytologia (August2007) 89(2) 197 UWVtRglfOf Fig. 2.Ageratinaserboana (Holotype).